Circuit interrupter employing means for controlling metallic vapor emission



Sept. 15, 1959 E. w. BOEHNE 2,904,659

CIRCUIT INTERRUPTER EMPLOYING MEANS FOR CONTROLLING METALLIC VAPOR EMISSION Filed April 9, 1957 2 Sheets-Sheet l v awe kart ang gunk.

United States Patent CIRCUIT INTERRUPTER EMPLOYING MEANS FOR CONTROLLING METALLIC VAPOR EMISSION This invention relates to electric circuit interrupting devices, and more particularly to air circuit breakers of the magnetic blowout type. r

It has been known for some time that are vapor is one of the worst enemies in the performance of alter,- nating or direct current circuit breakers. Vaporized metal in the arc stream tends to maintain and stabilize thearc thus hindering its interruption. In view of the fact that the metallic contentof the arc stream depends principally upon metal vapors or particles derived from the arc runners it is important that the ends of the arc in contact with the arcrunners be kept moving con tinuously in order to avoid heat concentrations and the consequent high vaporizing action; Inasmuch as arcs efiiecta vaporizing action of the materials used in the construction of an arc extinguishing device and since such vaporization tends to cause restriking' of the are at the exhaust end of the arc chute it is desirable to not only control the amount of metallic vapors but also its movement through the arc chute structure.

lrraccorda'nce with the invention claimed, a new and improved compact circuit breaker structure is provided comprising a pair of relatively movable contacts, means for drawing an arc between said contacts, and an arc chute for receiving the arc at one end thereof and exhausting the are products at the other end. The chute comprises a plurality of spaced insulating plates arranged to extend longitudinally of the axis of the chute at the are receiving end thereof and a pair of chimney vents arranged longitudinally of the axis of the chute, one adjacent to each end of said barrier plates. A magnetic coil is arranged adjacent to the contacts for driving the arc into the chute. In order to expedite the movement or the are into the arc chute a pair of arc runners are provided one arranged adjacent each of the contacts for providing a conductive path for the terminals of 'the are from the contacts into the chimney vents. The are runners are wrapped around at leasta part of the coil and extend upstream therefrom to a positionwithin the entrance ends of the chimney vents.

It is, therefore, one object of the present invention to provide a new and improved arc interrupting device.

Another object of this invention is to provide a new and improved arc interrupting device in which the vaporizing action of the are on the arc runners of the device is minimized.

A further object of this invention is to provide a new and improved arc interrupting device in which the arc vapors are confined and directed in a'predeterrnined "ice manner through the arc chute to assist in the extinction of the arc.

still further object of this invention is to provide a new and improved circuit breaker structure in which the terminals of the are are oscillated back and forth along the arc runners during an arcinterrl pting action, thus minimizing the generation of metallic ions. A still further object of this invention is to provide an improved arc runner of a predetermined configuration for minimizing metallic vaporization therefrom.

Objects and advantages other than those set forth will be apparent from the following description when read in connection with the accompanying drawings, in which: Fig. 1 is a view in vertical cross section of a magnetic. blowout type of circuit breaker employing the present invention;

Fig. 2 is a cross sectional view through the Contact structure'of Fig. 1 taken along the linefIIII;

Fig.3 is'a partial view in vertical cross section of a modification of the arc chute structure of the magnetic blowout type of circuit breaker illustrated in Fig. 1;

Fig.4 is a plan view of the structure illustrated in Fig. 3;

Fig. '5 is a cross sectional View through the arc chute structure of Fig. 3 taken along the line VV; and

Fig. 6 is a partial plan view of a modification of the splitter piate and chimney vent structure shown in Figs. 1-5. I Referring more particularly to the drawings by characters of reference, Fig. 1 illustrates a magnetic blowouttype of circuit breaker employing an arc chute into which the arc is forced by the magnetic blowout field and extinguished. The power circuit to be. inter rupted includes relatively movable contacts between which the arc is formed when the contacts separate at the entrance to the arc chute. Specifically, the contacts comprise a fixed contact structure 11 and a coacting movable contact structure 12. The fixed contact structure is electrically connected to a lead in conductor stud 13 defining one terminal of the breaker, and the movable contact structure 12 comprising a pivoted switch arm having an arcing contact mounted at one end thereof is electrically connected to a conductor stud 15 defining the,

other breaker terminal. The pivoted contact structure 12 is "suitably operated between open and closed circuit position by an operating rod 16 that is connected through a crank 17 toa solenoid or other operating means 18.

Fig. 1 illustrates the movable contact structure 12 in contact open position, the coacting main and arcing contacts 20 and 22, respectively, of the movable contact structure being spaced apart from corresponding main and arcing contacts 23 and 25, respectively, of the fixed contact structure 11. A pair of lugs 21 (one of which is' shown in Fig. 1) are integrated with arcing contact 22 and extend from opposite sides of a web portion of arcing contact 22. Lugs 21 together with the web por tion of" the arcing contact 22 form an engaging surface which coacts with that of a block of insulating material 24 on the stationary contact structure 11 to limit overtravel of the movable contact structure 12 in the closing In breaker closed position the stationary arcing Contact 25 is shunted by stationary maincorr" tact 23. Open n .Of the breaker by the clockwise rota direction.

3 tion of the breaker movable contact structure 12 causes in the sequence named separation of the main current carrying contacts 20, 23 and the arcing contacts 22, 25. The power arc is formed at the entrance of an arc chute 26.

Arc chute 26 is illustrated as being provided with magnetic blowout means comprising blowout coils 28 and 29 arranged so as to cause the arc formed between the contacts 22 and 25 to be blown by the magnetic field into arc chute 26. Blowout coil 28 is connected at one end thereof to a conductive arc runner 30 and at the other end thereof immediately adjacent main contact 23. Blowout coil 29 is connected at one end thereof to a conductive arc runner 31 and at the other end thereof to a lower terminal extension 32 through a conductive bar 27.

Upon separation of the arcing contacts 22 and 25 in a circuit interrupting action the arc terminal is transferred from stationary arcing contact 25 to are runner 30, thereby inserting blowout coil 28 in the arcing circuit traced from the point of connection of blowout coil 28 on the upper terminal block immediately adjacent main contact 23 through blowout coil 28 to are runner 30, through the arc to movable arcing contact 22. As the are, now established between arc runner 30 and the movable arcing contact 22, is attenuated by the clockwise rotation of contact structure 12, the arc envelops the lowermost portion of arc runner 31 thereby transferring the arc terminal from arcing contact 22 to are runner 31 and inserting blowout coil 29 in the arcing circuit. The arcing circuit is now completed through the bar 27 which connects the blowout coil 29 with the lower terminal extension 32.

Referring more particularly to the movable contact structure 12 of one phase of a three phase circuit, as shown in Figs. 1 and 2 of the drawings the switch arm comprises a pair of spaced plates 35 (one of which is shown in Fig. 1) mounted on a pivot bolt 36. The spaced plates 35 are also interconnected by a pin 37 which serves to connect the switch arm to the operating rod 16. Secured to the plates 35 and mounted on bolt 36 with the spaced plates 35 are a pair of spaced plates 38. Plates 38 extend generally parallel along the inside surfaces of plates 35 and are joined to plates 35 by any suitable means such as rivets 40. Plates 38 are joined together at their outer extremity by the contact body or head forming the current carrying contact 20 and the arcing contact 22.

Arranged between the spaced plates 35 and 38 is a hollow fluid conducting stationary bearing 39 for the reciprocating switch arm or movable contact structure 12. This bearing may be made of any suitable material sufficiently strong to stand the shock of circuit breaker operations such as cast bronze.

Bearing 39, more particularly, is arranged between conducting extensions 32 on bolt 36. Spaced plate combinations 35, 38 are yieldingly biased toward each other and against the opposite sides of bearing 39 by any suitable means which, for example, may be spring washers 33 secured to bolt 36 by a nut 34. Washers 33 are held in stressed condition against the sides of spaced members 35 by bolt 36 and nut 34, thus providing high contact pressure. Conducting ring inserts 41 are provided between plates 38 and conducting extension 32 to provide a line contact between the stationary and movable parts of this hinge connection. Bolt 36 which passes through suitable openings provided in spaced members 35, 38, extensions 32 and bearing 39, is provided with a closely fitting collar or shield 42 which serves to form a substantially fluid tight connection between the hollow opening in bearing 39 and the bolt 36.

The arcing contact structure and the arc chute of the circuit breaker structure are mounted on a supporting structure comprising a fabricated vehicular base structure 45. Mounted on base structure 45 is the circuit breaker operator 18 which may be a solenoid, pneumatic,

or a pneuma-oscillated hydraulic type of circuit breaker movable contact actuating means. A pair of dual purpose substantially vertical or diagonal tubular members 46 (one of which is shown in Fig. 1) are provided on base structure 45. Members 46 are connected to a horizontally arranged manifold 49 which supports a pair of horizontal cross bracing means 47 (only one of which is shown in Fig. 1). The circuit breaker elements comprising the movable contact mechanism of the circuit breaker and the arc chute are mounted on the horizontal cross bracing means 47 and the manifold 49. Members 46 in addition to supporting the circuit breaker, further collect and distribute to a zone of arc initiation fluid under pressure from a source of fluid under pressure such as a suitable pneumatic means 48 used for aiding in cooling and extinguishing an are drawn by the circuit breaker elements between the arcing contacts.

This pneumatic means comprises an air pump comprising a cylinder 50 mounted on base structure 45 and a piston 51 movable in cylinder 50. Piston 51 is biased in contact opening direction by an operating spring 59 which is'the means for opening the circuit breaker. The pneumatic means 48 serves a plurality of functions, namely, it is the motor actuating means for opening the contacts of the circuit breaker, it acts as an air pump to force air through the bearing 39 and nozzle 58 to aid in cooling and extinguishing the arc, and it acts as a shock absorber to retard the movement of the switch arm near the end of its opening stroke to reduce the impact of the movable contact structure 12 on the fixed structure of the circuit breaker. The solenoid operating means 18 through crank 17 returns piston 51 to its contact closed position after a circuit breaker opening operation and compresses spring 59 so it is capable of again opening the circuit breaker contacts. Any suitable means such as pipe connections 52 may be used for connecting the substantially vertically arranged tubular members 46 to the source of fluid under pressure, namely cylinders 50.

Manifold 49 is connected to the bearing 39 of each switch arm of each phase of the three phase circuit breaker through insulating tubular members 54. Bearing 39 comprising a hollow cylindrical member is provided with an outlet 55 (more clearly shown in Fig. 2). A slip ring 56 having attached thereto a tubular member 57 of high dielectric and flashover strength which terminates at its outer end in a nozzle 58 arranged adjacent the breaker elements in the zone of arc initiation is mounted around trunnion 39. Tubular member 57 is attached to the switch arm for movement therewith. As shown in Fig. l, tubular member 57 is generally arranged parallel with the switch arm in a predetermined relationship with the contacts 20 and 22. Slip ring 56 is arranged to provide a passageway for air under pressure from cylinder 50 through tubular member 46, manifold 49, tubular member 54, bearing 39, tubular member 57, and nozzle 58 to the zone of arc initiation. Tubular member 57 and nozzle 58 are secured to spaced plates 38 so that slip ring 56 and nozzle 58 move concurrently with plates 38 upon actuation of the arcing contacts to circuit open or circuit closed position.

For the purpose of interrupting either low or high current arcs the switch arm or movable contact structure 12 is connected to piston 51 through operating rod 16, crank 17 and a piston rod 64). Upon the movement of contact structure 12 from closed to open circuit position under the action of springs 59, piston 51 is actuated and moved from the top of cylinder 50 to the bottom of cylinder 58. This movement of piston 51 causes air in cylinder 58 under piston 51 to flow through pipe connections 52, tubular member 46, manifold 49, tubular member 54, bearing 39, tubular member 57 and nozzle 50 to the zone of arc. initiation. This blast of air under pressure cools the arc and drives it into the arc chute 26 for rapid arc extinguishing action.

-In accordance with the invention claimed arc chute 26 comprises a first group of slotted spaced insulating plates 62 arran ed to'extend longitudinally or the axis r the chute and transversely to the arc at the are receiving end thereof, second and third groups of spaced insulating splitter plates 63 and 64 arranged to extend longitudinally of the axis of the chute and substantially longitudinally of the arc with one'of the second and third groups of plates being arranged at each end of the first group, and a pair of chimney vents 65 and 66 arranged longitudinally of the axis of the chute one adjacent each of the second and third groups of splitter plates at the outer edges therec'if.

The'insulating barrier plates 62 of the first group may be arranged in a combination having a plurality of types of barrier plates having different geometrical configurations. Slots 67 of barrier plates 62 are aligned 'at their tripstrearn'ends adjacent the zone of arc initiation to form an arc passage. As well known in the art the slots may be arranged in staggered relation at their downstream ends; This out of registry or staggered relationship of the slots causes the formation of'a zigzag shaped arc path' Barrier plates 62 may be provided in some applications of this invention with a plurality of apertures o'r perforations which may be arranged to extend from the downstream ends of slots 67 toward the exhaust end of the are chute.

The second and third groups of splitter plates 63 and 64 each comprise four splitter plates arranged to extend transversely to the side walls of the chimney vents 65 66. As shown in Figs. 1, 3 and 4 the splitter plates are arranged in a vertical manner such as to receive the are vertically from the arc runner. The magneticforcs due to the field of the blowout coils as well as thenatural loop of the are current will drive the are into the splitter plate areas. The 'splitterplate groups may have any number of plates some or all of which may be provided witha plurality of apertures or perforations 80; extending therethrough for equalizing the gas'pressure within the various channels provided bythe splitter plates themselves. These channels are sometimeskno wn as the in terplate spacings.

"The chimney vents 65 and 66 are arranged at the ends or sides of the groups of splitter plates63 and '64 and above the arc runners 30 and 31. These vents'direct the are products and gases created by the arc terminals mew ing along the arc runners out of the arc chut'e'to atmosphere. The extent of the ionization of the gas'and the volume of the ar'c'products produced by the actionof the are on the arc runners vary directly with'the amount ofcur rent being interrupted and the'voltage characteris tics of the interrupter. It is recognized that the are products may interfere with the action of the barrier plate stack. Consequently chimney vents 6 and 66 are separated from the harrier plate and splitter plate'stacks and discharge the gases and are products from the'arc runners directly to atmosphere without going through these stacks.

As noted from the drawings the arc runners direct the terminals of the are into the chimney vents. These are runners are arranged to wrap around at least a part of the coil or coils ofmagnetic means 28, 29 and each extends upstrearn'therefrom to a position within or adjacent the entrance end of a different one of the chimney vents 65 and66. If so desired the arcrunners may be wrapped directly around the blowout coil or coils or merely positioned adjacent thereto and then extend therefrom upstream to the floor or base 70 of the' chimney vents in a smooth, gentle curve. In Figs. 1 and 3 the arc runners are shown as extending downstream'from the contacts, around at least a part of the magnetic means, upstream a'predeter'mined distance and into the entrance ends of the chimney vents. In passing into the entrance ends of the chirnney vents the arc runners extend upstream a predetermined distance across the are receiving end of the splitter plates and to a horizontal position in the chimney vents. The base or chimney portion of the largest voltage drop.

are runners is usually horizontal to the circuit breaker structure "and" extends into chimney vents 65 and 66 through apertures 71' and 72, respectively. As shown in Fig. 3 the wall surface 73 of chimney vent 65 or the same 'wall surface of chimney vent 66 may be provided with a plurality of apertures 74 adjacent the apertures or openings 71 and 72 for equalizing the gas pressure between the chimney vent and the adjacent stack of splitter plates.

Fig. 6 illustrates a modification of the splitter plate assemblies shown in Figs. 1-5 wherein the plates 75 of the stack are less in width than plates'76 and extend out from the wall 73 of the chimney vent 65 a shorter distance than do the plates 76.

When the arcing contacts 11 and 12 are separated to draw an arc, the arc terminals move from the contacts to approximately points 77 on arc'runners 30 and 31 and continue to run over arc runners 3t] and 31 until the terminals reach approximately the vent openings 71 and 72 in the chimney'vents 65' and 66. Up to this point in the interrupting action thearc column usually precedes the point of contact of the arc with the are runner. As the arc terminals pass openings 71 and 72 and move, into the chimney vents the arc column will trail the arc terminals along the arc runners. The are terminals after'reaching openings 71 and 72 in chimney vent Walls 73 will proceed rapidly into the base of the chimney vents due to the large magnetic forces acting on theourrent load and aided by the internal pressure within the arcing chamber. At this point inthe interrupting cycle of the arc the voltage drop across the extending arc column will increase and the arc will restrilce across the are runner between points closerto the crest of the arc runner curve, namely, near points 78. The are terminals will then proceed along the arc runners in the manner heretofore explained. This process of arc column extension and aim terminal movement along the arc runners will berepeatednumerous times until a current zerois forced or reached at which time interruption of the arc will take place. The pressures inside of the main arc chamber will act to drive the arc gases and are products up" the chimney vents and these gases and are products will be vented externally of the arc chute structure and separate from the exhaust of the main arc column.

The splitter plates of groups 63 and 64 are arranged in a vertical manner so as to receive the'ar'c running across the arc runner vertically therefrom. The magnetic forces due to the field of the blowout coil, as well'as the natural loop" of the arc current drives the arcinto the splitter plate areas. The are by traveling in a vertical manner at both sides of the arc chute develops its In the construction of the are chute shown in the drawings theblowout coils28 and 29 are arranged immediately below the barrier plates. In this manner the barrier plates, blowout coils and the current loop force the arc terminals into the chimney vents and the are adjacent thereto into the splitter'plat e areas to aid arc extinction.

The separate venting chimneys and are runner arrangement as disclosed above are not unalterablyassociated with the arc chute structure shown. New andother arc chute modifications are recognized as being possible with the venting chimneys as disclosed. In a similar manner other operating mechanisms are not be excluded as being within the scope of this invention;

Further, this new and improved circuit breaker stru c ture is adaptable for both alternating and direct current interrupting devices.

Although but a few embodiments of the present invention have been illustrated and described, it will be apparent'to'those skilled in the art that various changes and modifications may he made therein without departing from the spirit of the invention or from the scope of the appended claims.

"What is claimed is: 1. electric circuit interrupter comprising a pair of 7 7 relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the are products at the other end, said chute comprising a chimney vent, a magnetic coil arranged adjacent said contacts for driving the are into said chute, and an arc runner arranged adjacent said contacts for providing a conductive path for the terminal of the are from said contacts into said vent, said are runner being wrapped around at least a part of said coil and extending upstream therefrom to a position within the entrance end of said vent.

2. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the arc at one end thereof and exhausting the are products at the other end, said chute comprising a plurality of spaced insulating plates arranged to extend longitudinally of the axis of said chute at the arc receiving end thereof and a chimney vent arranged adjacent said plates, a magnetic coil arranged adjacent said contacts for driving the are into said chute, and an arc runner arranged adjacent said contacts for providing a conductive path for the terminal of the are from said contacts into said vent, said are runner being wrapped around at least a part of said coil and extending upstream therefrom to a position within the entrance end of said vent.

3. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the arc at one end thereof and exhausting the arc products at the other end, said chute comprising a plurality of plates and a pair of chimney vents arranged adjacent said plates, a magnetic means arranged adjacent said contacts for driving the are into said chute, and a pair of spaced are runners one being arranged adjacent each of said contacts for providing a conductive path for the terminals of the are from said contacts into each of said vents, said are runners being wrapped around at least a part of said magnetic means and extending upstream therefrom to a position within the entrance ends of said vents.

4. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the are products at the other end, said chute comprising a plurality of spaced insulating plates arranged to extend longitudinally of the axis of said chute at the are receiving end thereof and a pair of chimney vents arranged adjacent said plates, a magnetic means arranged adjacent said contacts for driving the are into said chute, and a pair of spaced arc runners one being arranged adjacent each of said contacts for providing a conductive path for the terminals of the arc from said contacts into each of said vents, said arc runners being wrapped around at least a part of said magnetic means and extending upstream therefrom to a position within the entrance ends of said vents.

5. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the arc products at the other end, said chute comprising a plurality of spaced insulating plates arranged at the are receiving end thereof and a pair of chimney vents arranged adjacent said plates, a magnetic means arranged adjacent said contacts for driving the are into said chute, and a pair of spaced arc runners one being arranged adjacent each of said contacts for providing a conductive path for the terminals of the are from said contacts into each of said vents, said are runners each extending downstream from one of said contacts, around at least a part of said magnetic means, upstream a predetermined distance and into the entrance end of one of said vents.

6. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between saidcontacts, an arc chute for receiving the are atone end thereof and exhausting the arc products at the other end, said chute comprising a plurality of spaced insulating plates arranged to extend longitudinally of the axis of said chute at the are receiving end thereof and a pair of chimney vents arranged adjacent said plates, a magnetic means arranged adjacent said contacts fordrivingthe are into said chute, and a pair of spaced arc runners one being arranged adjacent each of said contacts for providing a conductive path for the'terrninals of the, are from said contacts into each of said vents, said are runners each extending downstream from one ofsaid contacts, around at least a part of said magnetic means, upstream a predetermined distance and into the entrance end of one of said vents.

7. "An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the are products at the other end, said chute comprising a plurality of spaced insulating plates arranged to extend longitudinally of the axis of said chute at the arc receiving end thereof and a pair of chimney vents arranged adjacent said plates, a magnetic means arranged adjacent said contacts for driving the arc into said chute, and a pair of spaced arc runners one being arranged adjacent each of said contacts for providing a conductive path for the terminals of the are from said contacts into each of said vents, said are runners being wrapped around at least a part of said magnetic means and extending upstream therefrom to a horizontal position within the entrance ends of said vents.

8. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an arc between said contacts, an arc chute for receiving the are at one end thereof and exhausting the are products at the other end, said chute comprising a first group of spaced insulating plates arranged to extend longitudinally of the axis of said chute and transversely to the are at the arc receiving end thereof, a second group of spaced insulating splitter plates arranged to extend longitudinally of the axis of said chute and substantially longitudinally of the are at one end of said first group, and a chimney vent arranged longitudinally of the axis of said chute adjacent said second group at the outer edge thereof, and an arc runner arranged adjacent one of said contacts for providing a conductive path for a terminal of the arc from said one of said contacts across the are receiving end ofsaid second group and into said vent.

9. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the are products at the other end, said chute comprising a first group of spaced insulating plates arranged to extend longitudinally of the axis of said chute and transversely to the arc at the are receiving end thereof, a second group of spaced insulating splitter plates arranged to extend longitudinally of the axis of said chute and substantially longitudinally of the are at one end of said first group, and a chimney vent arranged longitudinally of the axis of said chute adjacent said second group at the outer edge thereof, a magnetic coilarranged adjacent said contacts for driving the are into said chute, and an are runner arranged adjacent one of said contacts for providing a conductive path for a terminal of the are from said one of said contacts into said vent, said are runner being wrapped around at least a part of said coil and extending upstream therefrom adjacent the arc receiving end of said second group to a position Within the entrance end of said vent.

10. An 'electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the. are at one end thereof and exhausting the arc products at the other end, said chute comprising a first group of 9 spaced insulating plates arranged to extend longitudinally of the axisof said chute and transversely to the are at the are receiving end thereof, a second'group of spaced insulating splitter plates arranged to extend longitudinally of the axis of said chute and substantially longitudinally of the are at one end of said first group, and a chimney vent arranged longitudinally of the axis of said chute adjacent said second group at the outer edge thereof, a magnetic coil arranged adjacent said contacts for driving the are into said chute, and an arc runner arranged adjacent one of said contacts for providing a conductive path for a terminal of the are from said one of said contacts into said vent, said are runner extending downstream from one of said contacts, around at least a part of said coil, upstream a predetermined distance across the are receiving end of said second group and to a horizontal position within the entrance end of said vent.

11. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an arc between said contacts, an arc chute for receiving the are at one end thereof and exhausting the are products at the other end, said chute comprising a first group of spaced insulating plates arranged to extend longi tudinally of the axis of said chute and transversely to the arc at the are receiving end thereof, second and third groups of spaced insulating splitter plates arranged to extend longitudinally of the axis of said chute and substantially longitudinally of the are, one of said second and third groups being arranged at each end of said first group, and a pair of chimney vents arranged longitudinally of the axis of said chute one adjacent each of said second and third groups at the outer edges thereof, and a pair of spaced arc runners one being arranged adjacent each of said contacts for providing a conductive path for the terminal of the are from said contacts across the are receiving ends of said second and third groups and into each of said vents.

12. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the are products at the other end, said chute comprising a first group of spaced insulating plates arranged to extend longitudinally of the axis of said chute and transversely to the are at the are receiving end thereof, second and third groups of spaced insulating splitter plates arranged to extend longitudinally of the axis of said chute and substantially longitudinally of the arc, one of said second and third groups being arranged at each end of said first group, and a pair of chimney vents arranged longitudinally of the axis of said chute one adjacent each of said second and third groups at the outer edges thereof, a magnetic means arranged adjacent said contacts for driving the are into said chute, and a pair of spaced arc runners one being arranged adjacent each of said contacts for providing a conductive path for the terminals of the arc from said contacts into each of said vents, said are runners being wrapped around at least a part of said magnetic means and each extending upstream therefrom adjacent the are receiving end of said second and third groups to a position within the entrance end of said vents.

13. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the are products at the other end, said chute comprising a first group of spaced insulating plates arranged to extend longitudinally of the axis of said chute and transversely to the are at the are receiving end thereof, a second group of spaced insulating splitter plates arranged to extend longitudinally of the axis of said chute and substantially longitudinally of the are at one end of said first group, at least some of said splitter plates being provided with a plurality of apertures for equalizing the fluid pressure within the interplate spacings, a chimney vent arranged longitudinally of theaxis of said chute adjacent said second gro p at the outer edge thereof and an'arc runner arranged adjacent one of said contacts for providing a conductive path for a terminal of the are from said one of said contacts across the are receiving end of said second group and into said vent.

14. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the arcproducts at the other end, said chute comprising a first group of spaced insulating plates arranged to extend longitudinally of the axis of said chute and transversely to the are at the are receiving end thereof, a second group of spaced insulating splitter plates arranged to extend longitudinally of the axis of said chute and substantially longitudinally of the are at one end of said first group, a chimney vent defined by a wall surface arranged longitudinally of the axis of said chute adjacent said second group at the outer edge thereof, a magnetic coil arranged adjacent said contacts for driving the are into said chute, and an arc runner arranged adjacent one of said contacts for providing a conductive path for a terminal of the are from said one of said contacts into said vent, said arc runner being wrapped around at least a part of said coil and extending upstream therefrom adjacent the are receiving end of said second group to a position within the entrance end of said vent, said wall surface being provided with a plurality of apertures arranged adjacent the are receiving end of said vent for equalizing the gas pressure between said vent and said second group of splitter plates.

15. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the arc products at the other end, said chute comprising a first group of spaced insulating plates arranged to extend longitudinally of the axis of said chute and transversely to the are at the arc receiving end thereof, a second group of spaced insulating splitter plates arranged to extend longitudinally of the axis of said chute and substantially longitudinally of the arc at one end of said first group, at least some of said splitter plates being provided with a plurality of apertures for equalizing the fluid pressure within the interplate spacings, a chimney vent defined by a wall surface arranged longitudinally of the axis of said chute adjacent said second group at the outer edge thereof, a magnetic coil arranged adjacent said contacts for driving the are into said chute, and an arc runner arranged adjacent one of said contacts for providing a conductive path for a terminal of the are from said one of said contacts into said vent, said are runner being wrapped around at least a part of said coil and extending upstream therefrom adjacent the are receiving end of said second group to a position within the entrance end of said vent.

16. An electric circuit interrupter comprising a pair of relatively movable contacts, means for drawing an are between said contacts, an arc chute for receiving the are at one end thereof and exhausting the are products at the other end, said chute comprising a first group of spaced insulating plates arranged to extend longitudinally of the axis of said chute and transversely to the are at the are receiving end thereof, a second group of spaced insulating splitter plates arranged to extend longitudinally of the axis of said chute and substantially longitudinally of the are at one end of said first group, at least some of said splitter plates being provided with a plurality of apertures for equalizing the fluid pressure within the interplate spacings, a chimney vent defined by a wall surface arranged longitudinally of the axis of said chute adjacent said second group at the outer edge thereof, a magnetic coil arranged adjacent said contacts for driving the are into said chute, and an arc runner arranged adjacent one of said contacts for providing a conductive path for 11 a terminal of the are from said one of said contacts into said vent, said are runner extending downstream from one of said contacts, around at least a part of said coil, up stream a predetermined distance across the are receiving end of said second group and to a horizontal position within the entrance end of said vent, said Wall surface being provided with a plurality of apertures arranged adjacent the are receiving end of said vent for'equalizing the gas pressure between said vent and said second group of splitter plates.

7 References Cited in the file of this patent UNITED STATES PATENTS Scott Oct. 14, Boehne Aug. 18, Baskerville May 2, Frank et al. May 19, Ridgley June 23, Taylor Aug. 11, Boehne Oct. 25, Spears Feb. 14, 

